Whole cereal grains are nutritious and provide high dietary fiber content. Sheeted or molded products have been made with whole grain wheat. Generally, rotary molded snacks and sheeted snacks are typically made with raw wheat flour. Wheat is unique in that it contains gluten, which helps to retain water, and provides cohesiveness and elasticity during machining. In a rotary molding process, even though gluten is not developed, much of the cohesiveness of dough comes from high addition levels of plastic shortening and to some extent from sugar in the formulation. In a sheeting process, gluten is developed which keeps the dough cohesive. Doughs made with other grain flours besides wheat flour do not tend to form cohesive dough because of their unique compositions which lack gluten, even in the presence of high levels of plastic shortening and sugar in the dough formulation. In particular, starch-based dough compositions, which have little or no gluten, when mixed with water, do not tend to form dough that is cohesive at room temperature and continuously machinable or sheetable.
U.S. Pat. Nos. 4,623,548 and 4,623,550 describe dough that is prepared using pre-gelatinized cereal flours/starches, partially gelatinized cereal flours/starches, and raw flours/starches to form dough having moisture of 40-50% for preparing extruded and sheeted fried snacks. Gelatinization is a function of water penetration into the whole berry, temperature, and time, for a given type of grain. According to U.S. Pat. No. 4,179,527, the gelatinization of wheat starch involves a destruction of bonds in the crystalline regions of starch granules.
In U.S. Pat. No. 897,181, cereal grain or vegetable in whole form is wetted but not cooked and then passed repeatedly between grooved rollers and then baked. Boiling or steaming of the grain or vegetable, it is disclosed, produces considerable change in its chemical quality and a number of the nutritious soluble elements escape to the water.
In U.S. Pat. No. 3,462,277, a mixture of cereal flour or grits and water is passed through an extruder to gelatinize the starch while the dough is cooked and transformed into a rubber-like mass. The moisture content of the mixture is 13 to 35%. The continuous U-shaped extrudate is pinched off into segments by cutting rolls to form canoe-shaped cereal products. The separated canoe-shaped pieces are then dried to below 15% moisture.
In U.S. Pat. No. 3,512,990 a dough, made from farinaceous materials such as wheat, corn, oats, rice, potatoes, or legumes, is optionally partially or completely cooked with added moisture, to an approximate moisture content of about 30%. After this cooking step, the mixture is rendered homogeneous by passing it through an extruder or a hammer mill, such as Fitzmill. The milled or extruded product is dried to an approximate moisture content of 22 to 24%. The dried dough is then compacted between two rolls to provide a shredding effect and produce a sheet of dough having diamond-like regularly spaced perforations. The sheet of dough is then severed into strips, folded to form small biscuits, which are closed on three, sides and then deep-fried.
In U.S. Pat. Nos. 987,088, 1,019,831, and 1,021,473, corn or another grain is ground and immersed in an amount of water which is limited to that which will be taken up by the grain during cooking. The purpose of this is to preserve in the cooked article the aroma and other properties of the grain, which might otherwise be carried off or dissipated by the evolution of steam or vapor. In these processes, the cooked dough is extruded through a perforated plate to obtain filaments.